A CO2 Concentrating System in Leaves of Higher C3-Plants Predicted by a Model Based on RuBP Carboxylase/Oxygenase Kinetics and 14CO2/12CO2 Exchange

Mächler, F., Lehnherr, B., Schnyder, H. and Nösberger, J. 1985. A CO2 concentrating system in leaves of higher C3-plants predicted by a model based on RuBP carboxylase/oxygenase kinetics and 14CO2/12CO2 exchange.−J. exp. Bot. 36: 1542-1550. A model is presented which compares the ratio of the two activities of the enzyme nbulose bisphosphate carboxylase/oxygenase as determined in vitro with the ratio of photosynthesis to photorespiration in leaves as determined from differential 14CO2/12CO2 uptake or from CO2 compensation concentration. Discrepancies between measurements made in vitro and in vivo are attributed to the effect of a CO2 concentrating system in the leaf cells. Interference from dark respiration is discussed. A CO2 concentrating system is postulated which is efficient mainly at low temperature and low CO2 concentratio